Dust-proof watchcase-pendant.



M. ROSENHAFT. DUST Pnoor wAToHoAsE PENDANT.

APPLICATION FILED DBO. 5, 1,907.

mmm-,ed 0011.211908,

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MICHAEL ROSENHAFT, OF HAMBURG, GERMANY.

DUST-PROOF WATCI-ICASE-PENDANT.

Specification of Letters Patent.

Patented Oct. 27, 1908.

Application filed December 5, 1.*907. Serial N o. 405,138.

To all 'whom 'it may concern:

Be it known that I, MICHAEL RosENHAFT, a citizen of Germany, residing at Hamburg, Germany, have invented new and useful Improvements in Dust-Proof Watchcase-Pendants, of which the following is a specification.

The known pendants of stem-winding or keyless watches have the drawback, that they do not sufiiciently protect the works against the entrance of dust. The parts connected with the crown, for instance the stem, are simply inserted in the mechanism through the pendant. As however these parts must be revoluble they cannot fit tightly against the walls of the pendant, whereby interstices are formed through which dust can directly enter.

By the arrangement which forms the object of this invention the drawbacks are removed by the guide piece connected with the crown engaging in a grooved recess in the pendant, and these two parts forming a mutually interconnected neck by means oi threads or grooves which are formed on some of the adjacent faces. By this arrangement the penetration of dust into the mechanism through the pendant part is entirely avoided, as the dust remains lying in the channel and also even if it should take the opposite course, is prevented by the screw thread from penetrating further.

rihe accompanying drawing represents a longitudinal section of a watch pendant embodying my invention.

The part -aof the pendant is formed with a groove or socket tapering con ically in its lower part, the inner wall cof which is smooth at the lower portion and provided with a thread at the upper portion. 'Ihe guide piece or crown hub f, attached to the crown d, and the other parts, for instance the stem e connected therewith, is also recessed to form a tubular sleeve which enters socket b.

This sleeve has on its inner face g l counter threads corresponding to the threads of the pendant. The upper art of the recess is smooth. A ldownwar ly tapering recessed tubular projection h of the guide part also engages in a corresponding recess in the pendant. Now dust, in order to reach the Works, must penetrate the space between a and f, and that between f and c and finally that between a and 7L. The object of providing the smooth part is to allow of' the mutual mobility of the parts Without executing a spiral movement. In watches in which the throwing into and out oit' action of the hands mechanism for the purpose of displacing the hands is operated from the crown, the smooth parts are made longer.

I claim- 1. 'A watch pendant having a socket provided with an upper thread and a lower smooth face, combined with a crown hub entering said socket and having an upper smooth face and a lower thread, the thread on one of said parts being opposed by the smooth face of the other part, substantially as speciiied.

2. A watch pendant having an inner recess and an outer socket, said socket being provided with an upper thread and a lower smooth face, combined with a crown hub having a tubular projection entering said recess, and a sleeve entering said socket, the sleeve having an upper smooth tace and a lower thread, the thread on the sleeve being opposed by the smooth face of the socket, while the smooth face of the sleeve is opposed by the thread of the socket, substantially as specii'ied.

Signed by me at Hamburg, Germany this 22nd day of November 1907.

MICHAEL ROSENHAFT.

Witnesses:

HAMILTON RnsnK, ERNEST H. L. MUMMENHOFF 

